One of the first things you may notice when traveling to or living in Korea is that measurements can look very different from what you're used to in the United States.
1.Kilometers vs. Miles
This is probably one of the most important differences when traveling between Korea and the U.S.
Korea uses kilometers (km) for road distances and speed limits.
The U.S. uses miles (mi).
The exact conversion
1 mile = 1.609 kilometers
1 kilometer = 0.621 miles
For everyday situations, you can remember:
1 mile ≈ 1.6 km
1 km ≈ 0.6 miles
Easy examples
| Korea | Approximately in the U.S. |
| -----: | ------------------------: |
| 1 km | 0.6 miles |
| 5 km | 3.1 miles |
| 10 km | 6.2 miles |
| 20 km | 12.4 miles |
| 50 km | 31 miles |
| 100 km | 62 miles |
So if someone in Korea says :
"It's about 10 km away."
You can think :
"That's about 6 miles."
If a GPS says you have 30 miles to go in the U.S., that's about 48 km.
A useful mental trick
To convert km → miles, take about 60% of the kilometer number.
For example :
10 km → about 6 miles
50 km → about 30 miles
100 km → about 60 miles
2.Meters, Feet, and Inches
Korea commonly uses meters and centimeters, while the U.S. commonly uses feet and inches for height, room dimensions, and other everyday measurements.
The important conversions
1 meter = 3.28 feet
1 foot = 30.48 cm
1 inch = 2.54 cm
For quick estimates :
1 meter ≈ 3.3 feet
1 foot ≈ 30 cm
1 inch ≈ 2.5 cm
Example : Height
A person who is 180 cm tall is about :
1.80 meters
or approximately
5 feet 11 inches
In the U.S., people often say:
"I'm 5'11".
Quick height guide
| Korean height | Approx. U.S. height |
| ------------: | ------------------: |
| 150 cm | 4'11" |
| 160 cm | 5'3" |
| 165 cm | 5'5" |
| 170 cm | 5'7" |
| 175 cm | 5'9" |
| 180 cm | 5'11" |
| 185 cm | 6'1" |
| 190 cm | 6'3" |
You don't need to calculate this every time. After seeing a few common heights, you'll start to recognize them automatically.
3.Celsius vs. Fahrenheit
Temperature is another major difference.
Korea uses Celsius (°C).
The United States uses Fahrenheit (°F).
This can be confusing because the numbers are completely different.
For example :
20°C feels like about 68°F.
30°C feels like about 86°F.
0°C is 32°F.
The exact formulas
To convert Celsius to Fahrenheit :
°F = (°C × 9/5) + 32
To convert Fahrenheit to Celsius :
°C = (°F − 32) × 5/9
But you don't need to use the exact formula every time.
Easy temperature chart
| Celsius | Fahrenheit | How it feels |
| ------: | ---------: | ------------- |
| -10°C | 14°F | Very cold |
| 0°C | 32°F | Freezing |
| 5°C | 41°F | Cold |
| 10°C | 50°F | Cool |
| 15°C | 59°F | Mild/cool |
| 20°C | 68°F | Comfortable |
| 25°C | 77°F | Warm |
| 30°C | 86°F | Hot |
| 35°C | 95°F | Very hot |
| 40°C | 104°F | Extremely hot |
The easiest temperatures to memorize
0°C = 32°F
10°C = 50°F
20°C = 68°F
30°C = 86°F
40°C = 104°F
Once you know these, you can estimate most everyday temperatures.
A quick mental formula
For a rough estimate :
Double the Celsius temperature and add 30.
For example :
20°C → 20 × 2 + 30 = 70°F
The actual temperature is 68°F, so this is close enough for casual conversation.
30°C → 30 × 2 + 30 = 90°F
The actual temperature is 86°F.
This is only an approximation, but it is very useful when you just want to know whether the weather is cool, warm, or hot.
4.Kilograms vs. Pounds
Korea uses kilograms (kg) and grams (g).
The U.S. commonly uses pounds (lb) and ounces (oz).
This difference comes up often when talking about:
- Body weight
- Luggage
- Food
- Packages
- Gym weights
- Shipping
The exact conversion
1 kilogram = 2.205 pounds
1 pound = 0.454 kilograms
For everyday calculations, remember :
1 kg ≈ 2.2 lb
1 lb ≈ 0.45 kg
Quick weight chart
| Korea | Approximately U.S. |
| -----: | -----------------: |
| 1 kg | 2.2 lb |
| 5 kg | 11 lb |
| 10 kg | 22 lb |
| 20 kg | 44 lb |
| 30 kg | 66 lb |
| 50 kg | 110 lb |
| 60 kg | 132 lb |
| 70 kg | 154 lb |
| 80 kg | 176 lb |
| 90 kg | 198 lb |
| 100 kg | 220 lb |
Easy mental trick
To convert kg → l*, simply double the number and add about 10%.
For example :
70 kg
Double it :
140
Add 10% :
14
So :
70 kg ≈ 154 lb
5.Grams vs. Ounces
For smaller amounts, Korea commonly uses grams (g).
The U.S. often uses ounces (oz).
The exact conversion is :
1 ounce ≈ 28.35 grams
For quick calculations :
1 oz ≈ 28 g
30 g ≈ 1 oz
Examples
100 g ≈ 3.5 oz
200 g ≈ 7 oz
500 g ≈ 17.6 oz
1,000 g = 1 kg ≈ 35.3 oz
This can be especially useful when comparing food packages.
6.Speed : km/h vs. mph
There's another important difference when driving.
Korea uses kilometers per hour (km/h).
The U.S. uses miles per hour (mph).
The conversion is :
1 mph ≈ 1.61 km/h
1 km/h ≈ 0.62 mph
Easy examples
| Korea | U.S. |
| -------: | -----: |
| 30 km/h | 19 mph |
| 50 km/h | 31 mph |
| 60 km/h | 37 mph |
| 80 km/h | 50 mph |
| 100 km/h | 62 mph |
| 120 km/h | 75 mph |
A very useful shortcut :
100 km/h ≈ 62 mph
So if you're driving at 100 km/h in Korea, you're going roughly 62 mph.
The goal is not perfect mathematical precision. The goal is to quickly understand how far, how heavy, how tall, or how hot something is.
Once you memorize a handful of these reference points, switching between Korean and American measurements becomes much easier.
